The present invention relates to an improved electrified composite metal/concrete floor.
Such floors are well known and comprise a corrugated metal decking over which concrete is poured. Such floors are often electrified in that electrical power and telephone and other communication services are distributed in the cells underlying the raised portions or crests of the decking, with access to the interior of the cells from the upper surface of the floor provided by inserts preset at selected intervals prior to the concrete pour. Access of the services to the interior of the longitudinal cells is generally provided by a lateral trench overlying the metal decking, which trench includes parallel rails covered with a metal plate coplanar with the upper surface of the concrete floor when poured.
In one aspect, the present invention includes a novel metal decking profile, with grooves adjacent the lateral edges of the crests to receive the concrete of the composite floor, stable when stacked during shipment to the job site.
Grooves adjacent the crests of decking to receive concrete are well known. For example, FIG. 4 of the French Pat. No. 1,176,824 granted Nov. 28, 1958 to Wendel shows a decking profile in which the radii of the bend at the lateral edge of the crest and the bottom of the groove are equal and in which the centers for the bends are vertically spaced approximately twice such radii. Concrete enters the groove to enhance the metal/concrete interaction when the concrete is poured. Stacking is stabilized by making the radius bend of the lateral edge of the lower side of the groove slightly larger than such radii to mate with the lateral edge of an underlying decking member. However, the semi-cylindrical radius bends will not permit adequate concrete entry when used with cover plates, and do not provide adequate deformation resistance to downward pressure from the lateral edges of the crests.
Grooves adjacent the lateral edge of metal decking are also shown in the Ting U.S. Pat. No. 4,453,364 dated June 2, 1984. In that patent, the grooves have a horizontal lower side and an upper side joining the radius bend of the lateral edge of the crest at an angle of approximately forty-five degrees. The Ting grooves are constructed such that a vertical line passing through the lateral edge intersects the lower side of the groove rather than the side wall of the valley and such that the intersection of the planes of the side wall and crest is at or outside the lateral extremity of the crest, i.e., the center of the bends of the crest, groove and side wall are horizontally displaced from each other. While resistance is enhanced, the amount of concrete which can enter the groove is inadequate when cover plates are used. Moreover, the location of the lateral edge of the crests interiorly of the intersection of the planes of the side wall and crest results in instability in stacking.
The decking profile of the present invention combines the stacking stability of Wendel with the improved strength of Ting and enhances the metal/concrete interaction. In one embodiment, this improvement is obtained by increasing the vertical separation of the centers of the radius bends of the crest and groove so as to join the groove and crest edge at an angle of approximately forty-five degrees. Stacking stability is enhanced by the matching of the radius bends of the side wall and crest.
In another embodiment, the decking profile of the present invention further enhances the concrete/groove interface by establishing a projection in the side wall immediately below the groove to thereby extend the horizontal lower wall of the groove. Stability when stacked is enhanced by the abutment of the projection with the side wall at a point on the side wall below the crest.
In another aspect, the present invention includes snap-in cover plates for selected valleys of the decking to form longitudinal cells for electrification of the floor. Longitudinal cells for this purpose are well known. They may be formed by welding of the decking to an underlying plate as disclosed in the Penczak U.S. Pat. No. 4,041,238 dated Aug. 9, 1977, the Fork U.S. Pats. No. 4,178,469 dated Dec. 11, 1979, or No. 3,426,802 dated Feb. 11, 1969; or the Littrell U.S. Pat. No. 4,338,484 dated July 6, 1982. They may also be formed by snap-in plates beneath the crests of the decking as disclosed in the Fork U.S. Pat. No. 4,194,322 dated Mar. 25, 1980, and the Albrecht, et al. U.S. Pat. No. 3,812,636 dated May 28, 1974. The decking is, however, structurally weakened by the apertures necessary for access to the cells.
Others such as disclosed in the Fork European Pat. No. 0003506, the Fork U.S. Pat. No. 3,592,956 dated July 13, 1971, or the Lee, et al. U.S. Pat. No. 2,912,848 dated Nov. 17, 1959 have provided cover plates for a valley to thereby create longitudinal cells.
However, such systems generally provide a smooth upper surface with reduced metal/concrete interaction, do not provide for separation of services within the cell, span the valley without intermediate support, are not resiliently compressible for snapin and do not have upturned lateral edges for prevention of water seepage during the concrete pour.
Other systems such as disclosed in the Ting U.S. Pat. application Ser. No. 340,869 filed Jan. 20, 1982 (now abandoned) utilize grooves adjacent the crests for retention of the cover plates. While this provides an upturned edge for prevention of water seepage, the reduced height of the cell is generally unacceptable in that the reduced volume will not accommodate a duplex receptacle. Moreover, concrete/metal interaction is significantly reduced by the flat surface and the substantial filling of the groove of decking by the edge of the cover plate as shown in FIGS. 4 and 5 of the Ting application. The Ting application teaches support of the cover plates intermediate the crests. However, the separation of the cell into two services by two interconnected but spaced apart legs further reduces the volume of the two cells, when three are needed.
The cover plates of the present invention are stackable for shipment to the job site and are easily installed from above the decking, thus greatly reducing installation costs. In one embodiment, they may be made of sheet metal and provided with two double walled legs to provide support intermediate the crests. The legs may be constructed to provide resiliency and thus secure engagement with the grooves. Metal/concrete interaction is also enhanced, and additional space for three services provided, by the selective raising of position of the cover plate to the same height of the crests, and by a decking profile which permits the entry of substantial concrete into the grooves even with the lateral edges of the cover plate engaged therein.
In still another aspect, the present invention includes a preset insert uniquely cooperating with the cover plates for access to the cells defined by the decking valley and cover plate. Known preset inserts such as disclosed in the Fork et al U.S. Pat. No. 3,932,696 dated Jan. 13, 1976 and Penczak U.S. Pat. No. 4,041,238 dated Aug. 9, 1977 span adjacent crests and are designed to provide access to cells beneath the crests. Others such as Fork U.S. Pat. No. 3,417,191 dated Dec. 12, 1968 fit between the crests to provide access to cells beneath the crests, and still others such as Fork U.S. Pat. No. 3,592,956 dated July 13, 1971 span two crests to provide access to cells beneath adjacent crests as well as a cell in the intervening valley.
In various embodiments, the preset inserts of the present invention are stackable for shipment to the job site, may be constructed of sheet metal, provide ready access to all three longitudinal cells, and cooperate with snap-in electrical power receptacles.
In the present invention, preset inserts may be carried solely by the cover plates and either, or both, may cooperate with the grooves in the decking without significant diminution of the area of the cell.
In yet another aspect, the present invention includes a novel lateral trench for distribution of the services to the longitudinal cells. Prior art trenches such as disclosed in the Fork U.S. Pat. No. 3,886,702 dated June 3, 1975 generally extrude vertically adjustable side rails of aluminum. Many of the above, such as Fork et al U.S. Pat. No. 3,932,696 dated Jan. 13, 1976 and Penczak U.S. Pat. No. 4,065,896 dated Jan. 3, 1978 utilize the crests of the decking as the floor of the trench and carry vertical concrete stops which depend into the valley. In this way, the valley floor of the decking also becomes the floor of the trench. Such trenches are often referred to as "bottomless". However, the use of the valley floor as the bottom of the trench requires that the concrete be interrupted by the depending stops to prevent filling of the trench with concrete from the valleys underlying the trench. Such interruption effects a significant loss of strength of the completed floor.
In various embodiments, the present invention in various aspects provides rails of sheet metal of greatly reduced cost, and snap-in bottoms for the trench intermediate the electrified cells. Concrete may thus flow uninterrupted through the non-electrified valley beneath the trench.